Over the years, a wide variety of games of chance have been devised to allow players to wager a sum of money for the opportunity to win greater sums of money. Such games include lotteries, bingo, keno, blackjack, poker, roulette, craps and slot machines. Of these games, many people find slot machines to be the most entertaining. For this reason, slot machines constitute a major source of profits for casinos.
It is of substantial value to a casino to encourage lengthier play sessions at a slot machine. When a player terminates play and walks away from a slot machine, that machine often goes unused for some period of time until a new player initiates play, thereby reducing revenue from that slot machine. Like any game of chance, the lengthier the play session, the larger the profit the casino stands to make. Casinos therefore constantly strive to increase the continuous playability time of slot machines.
In a basic mechanical slot machine, the player inserts a bill or coin and pulls down on the slot machine handle to initiate the game. Typically, three parallel, rotatable reels with an assortment of fruit, numbers, bars, or any other creative symbols are then caused to spin until each reel reaches a resting position. The success or failure of the game is determined by comparing the combination of reel symbols across a horizontal row with a table of winning combinations posted on the slot machine. To add interest to the game, the basic mechanical slot machine windows are frequently made large enough to show three adjacent symbols on each reel and thereby allow betting involving multiple rows. This betting can take the form, for example, of betting on the combinations formed across the upper horizontal row, middle horizontal row, lower horizontal row, and diagonal lines intersecting these rows.
With the advent of electronic technology, there have been many improvements to the mechanical slot machine. Among these improvements is the use of video monitors to display a simulation of three parallel, rotatable reels, rather than having three actual mechanical reels themselves. In operation, these electronic slot machines simulate the rotation of a physical reel, but typically select the final symbols through use of random numbers generated by a microprocessor rather than the physical rotation of a reel. In other words, the final symbols for each simulated reel in the electronic slot machine are randomly selected by the microprocessor and then displayed on the video monitor at the appropriate time and position.
The use of electronic technology for slot machines has allowed game designers to break free from the mechanical restrictions of earlier slot machines. For example, the number of combinations that can be displayed on a video monitor is no longer limited by the number of symbols that can be fit onto three physical reels. This opportunity for greater numbers of displayed combinations has led the way to greater jackpots and progressive slot machines. Also, with electronic technology, the three symbols shown in each column no longer need to correspond to three adjacent symbols on a physical reel. Through generation of different random numbers, each symbol displayed in a video monitor column can be independently generated, thereby decreasing the odds and inversely increasing the potential payout of any one game.
Nevertheless, both mechanical and electronic slot machines continue to suffer from several shared disadvantages. For example, one frequent frustration that players have with slot machines, even the new electronic slot machines, is that the initial spin of the slot machine does not allow the player to use strategy in selecting which columns and rows he wishes to spin and in what sequence, thereby increasing his probability of obtaining a winning combination. An additional frustration players face with mechanical and electronic slot machines is that the combination that is finally displayed along their betting line may fall just short of a winning combination and the player has no opportunity for adjusting the displayed combination.
It would be highly desirable to provide a slot machine, where a player is motivated, on a consistent and ongoing basis, to prolong session play by using strategy to sequentially select and spin columns and rows to build upon advantages gained in previous results.